CONCAT'ing NULL fields

Question

I have a table with three fields, FirstName, LastName and Email.

Here\'s some dummy data:

FirstName | LastName | Email
Adam        West       adam@west.c         


        

Answer 1

After observing the answers for this question, you may combine all of them into one simple solution

CONCAT_WS(',',
IF(NULLIF(FirstName, '') IS NULL, NULL, FirstName),
IF(NULLIF(LastName, '') IS NULL, NULL, usr_lastname),
IF(NULLIF(Email, '') IS NULL, NULL, Email))

So, in short we use CONCAT_WS to concatenate our fields and separate them with ,; and notice that NULL fields nor EMPTY wont concatenated

NULLIF will check if the field is NULL or EMPTY, a field that contains only spaces or is empty as well, ex: '', ' ') and the output will be either NULL or NOT NULL

IF Will out put the field if it's not NULL or EMPTY